Fortunately, the excitation maximum of green fluorescent protein is readily shifted to 488 nanometers (in the cyan region) by introducing a single point mutation altering the serine at position 65 into a threonine residue (S65T).

Further, acid hydrolysis would convert cysteine to cystine, and hydrolysis would destroy serine, threonine, cystine, cysteine, and arginine in the alkaline solution generally regarded to have characterized the early ocean.